FILE FORMAT -The specific way in which any file is saved. It is identified
by the three letter extension (IBM-compatible computers) or four+ letter
extension following a period (dot) at the end of the identifying file
name: filename.ext. Every format has its own characteristics,
advantages and disadvantages. You cannot just name change the file extension
to another set of letters; it must be converted for use in different programs.
Most graphic programs are able to perform the format conversion viz. you
can import a graphic with one file format extension and export it/save
it as another type of file format.

file
extension

acronym
meaning

definition

bmp

(pronounced
as separate letters)

BitMaPped
graphic

standard,
non-compressed bit-mapped graphics format used in the Windows. BMP files
store graphics in a format called device-independent bitmap (DIB). Bitmap
images, also called raster images, use a grid (the bitmap or raster) of
small squares known as pixels to represent images. Each pixel is assigned
a specific location and color value.

cgm

(pronounced
as separate letters)

Computer
Graphics Metafile

file
format designed to be a standard vector graphics file
format.
Supported by a wide variety of software, particularly word processing programs.

dib

(pronounced
as dib)

Device-Independent
Bitmap

bit-mapped
graphics format
used by Windows. When stored, the DIB format generally end with a .bmp extension
& represents colors in a format independent of the final output device.
When a DIB image is sent to output (to a monitor or printer), the device
driver translates the DIB to colors that the device can display.

eps

(pronounced
as separate letters)

Encapsulated
Post Script

graphics
file format used by the PostScript language. EPS files can be either binary
or ASCII. The term EPS usually implies that the file contains
a bit-mapped representation of the graphics for display purposes. In
contrast, PostScript files, referring
to fonts, include only the PostScript commands for printing the graphic.

fpx

(pronounced
as separate letters)

FlashPiX

format
for storing digital images,
especially digital photographs,
developed by Eastman Kodak Company. It has the ability to store various
resolutions of an image in a single file use of Microsoft's OLE structured
storage format, which enables developers to extend the format
built-in linking support so that different applications can link to the
same image in different ways.
IMPORTANT:
Currently, FlashPix is not supported by most imaging software.

gif

(pronounced
jiff or giff (hard g)

Graphics
Interchange Format

standard
bit-mapped graphics file format used by the World Wide Web developed by
CompuServe in the late 1980s. GIF supports 256 (216-on IBM-based monitors)
levels of color.

img

(pronounced
image)

IMaGe
graphic

format
handles monochrome and gray level images (originally designed to work with
the GEM Paint Program). VENTURA Publisher application supports the IMG file
format while various other desktop publishing applications have added support
for importing and exporting this format although usually not processing
it.

jpg
or jpeg

(pronounced
jay-peg)

Joint
Photographic ExpertsGroup

a
lossy data compression for color images especially effective for scanned
photos. There are varying levels of compression with varying loss of detail.
At the highest compression (lowest quality), it can reduce files sizes to
about 5% of their normal size. Lossy compression throws away some of the
graphic data every time it is used to save. It does not lose data when merely
opening a file, as on the Internet.

mac

(pronounced
mac)

MAC
paint graphic

monochrome
MacPaint graphic file format. In order to take a MAC file from a Macintosh
to a PC, a "MacBinary" header has to be added to the file format.
MAC images can be transferred "back" from a PC to a Macintosh.
The MAC format always requires an image width of 576 pixels and a height
of 720 lines. For that reason files converted to the MacPaint format from
other formats will be cropped or padded out as necessary to fit in the 576X720
pixels size.

pcd

(pronounced
as separate letters)

?
Photo Compact Disc graphic file

a
multi-resolution compressed file format created for KodakŪ Photo CD
files on Pro Photo CD discs. 5 levels of quality are in the format from
thumbnail (lowest quality, small size files) to 18M files for high quality
use. The Kodak Precision Color Management System (KPCMS) lets you control
the color mode and display of Photo CD images by specifying profiles for
the source film and the destination output device.
Note: You can open PCD files in one of the resolutions in Adobe Photoshop
but cannot save files in the Photo CD format.

pcx

(pronounced
as separate letters)

PC
paintbrush piX
by ZSOFT

a
graphics file format for graphics
programs running on PCs. It is supported by most optical scanners, fax programs,
and desktop publishing systems.

pdd
and psd

(pronounced
as separate letters)

?
PhotoShop Designated
file

native
Adobe Photoshop graphic file formats that takes up less memory than uncompressed
TIF files. Saves masks, layers, clipping paths, and alpha channels with
the graphic. Not a recognized import file for all programs.

pdf

(pronounced
as separate letters)

Portable
Document Format
by Adobe Acrobat

Identical
to PostScript pages, PDF files can represent both vector and bitmap graphics,
and can contain electronic document search and navigation features such
as electronic links. Photoshop PDF format supports RGB, indexed-color, CMYK,
grayscale, Bitmap, and Lab color modes, and does not support alpha channels.
The format supports JPEG and ZIP compression, except for Bitmap-mode files,
which use CCITT Group 4 compression when saved as Photoshop PDF. When you
open a PDF created by another application, Photoshop rasterizes the file.

pic

(pronounced
as pic)

PICtor
graphic file
generated and used by PICTOR, PC-Paint and GRASP.

16
color PIC files have a non-common structure in their color manifestations
& will produce a temporary scratch file while packing or unpacking a
16 color PIC file. Also used for Lotus Picture File, the graphics file format
used to represent graphics generated by Lotus 1-2-3. PIC file format is
not compatible with the Lotus 1-2-3 PIC drawing files

pict

(pronounced
as pict)

PICTure
file format

Mac
graphic file format used for and for screen display in page-layout applications
as an intermediary file format for transferring files between programs.
The PICT format supports RGB files with a single alpha channel, and indexed-color,
grayscale, and Bitmap files without alpha channels. It is not used for printed
images since the format does not carry the information needed for separations.

png

(pronounced
ping)

Portable
Network Graphics

a
new bit-mapped graphics format similar to GIF. Approved as a standard by
the WWW consortium to replace
GIF because GIF uses a patented data
compression algorithm called LZW. In
contrast, PNG is completely patent- and
license-free. Only the most recent versions of Netscape Navigator and Microsoft
Internet Explorer now support PNG.

raw

(pronounced
as raw)

RAW
graphic

a
flexible basic file format for transferring files between applications and
computer platforms. This format consists of a stream of bytes describing
the color information in the file. Each pixel is described in binary format,
with 0 equaling black and 255 white (for images with 16-bit channels, the
white value is 65535). You can specify the file extension (Windows), file
type (Mac OS), file creator (MacOS), and header information. It supports
CMYK, RGB, and grayscale files with alpha channels, and multichannel, Lab,
indexed-color, and duotone files without alpha channels.

tif
or tiff

(pronounced
as tif)

Tagged
Image File Format

one
of the most widely supported lossless (does not lose information during
compression) file formats for storing bit-mapped images (both PCs and Macintosh
computers). TIFF graphics can be any resolution, in black and white, gray-scaled,
or color. Is used un-compressed or LZW compressed.

tga

(pronounced
targa)

TarGA
format
developed by Truevision for their Targa and Vista products.

an
industry standard designed for high-end paint programs and ray tracing packages
on systems that use MS-DOS color applications. It is not as widely supported
as PCX or TIFF formats nor in Windows-only applications. It was one of the
first formats able to handle images with up to sixteen million unique colors.
TGA files may be saved compressed (run length encoded) or not compressed.

wpg

(pronounced
as separate letters)

WordPerfect
Graphic

file
format that can contain bitmaps, line art, and vector graphics. When using
an application other than WordPerfect for viewing a WPG file containing
both bitmapped and vector elements, the vector elements will be discarded.
This is why they may look poor in other programs.

I have tried to list
as many of the most common graphic file formats that are platform-independent
(unless otherwise noted), which means you can use them on a PC, Mac or UNIX
machine as long as you have a program that can use them.

For video, the popular extensions are .AVI for the PC, .MPG (short for MPEG)
which is platform-independent, but requires its own player and .MOV and .QT
for QuickTime movies which were initially just for the Macintosh, but are now
available for Windows and UNIX.

avi

(pronounced
avee)

Audio
Video Interleave

file
format for Microsoft's Video Windows standard.

fla

(pronounced
flash)

FLAsh

Macromedia's
FLASH working movie file. Upon completion of the Flash animation movie,
the file is exported from FLASH as an .swa movie file. As an .swa file,
the movie is no longer editable.

mpg
or mpeg

(pronounced
m-peg)

Moving
Picture ExpertsGroup

digital
video compression format that achieves a high compression rate by storing
only the changes from one frame to another, instead of each entire frame
(as in fli/flc). The video information is then encoded using a technique
called DCT. MPEG uses a type of lossy compression, that is generally imperceptible
to the human eye.
MPEG-1 standard provide a video
resolution of 352-by-240 at 30 frames per second (fps). This produces video
quality slightly below the quality of conventional VCR videos.
MPEG-2: offers resolutions of 720x480 and 1280x720 at 60 fps, with full
CD-quality audio. This is sufficient for all the major TV standards, including
NTSC (National Television Standard of Colors, and even HDTV. MPEG-2 is used
by DVD-ROMs. Requires significantly more processing
power.
MPEG-4: will be based on the QuickTime file format.

(AUDIO)
mpg
or mpeg

(pronounced
m-peg)

Moving
Picture ExpertsGroup

MPEG Audio:
basically it is the sound layer of an mpeg movie file. Currently seen
as:.mp, .mp2, .mp3, .m1a, .m2a, .mpg, .mpeg, .swa. MPEG also stands for
the "Moving Picture Experts Group". MPEG audio files can be
either layer I, II or III. Increasing layer numbers add complexity to
the format and require more effort to encode and decode. However, they
also provide higher playback quality for the sample bit rate. Audio MPEG
files come in two flavors, MPEG-1 and MPEG-2. The encodings for the three
layers are mostly the same; however, MPEG-2 streams have lower sampling
rates for better fidelity at lower bit rates. Files can have sampling
rates of 32000, 44100 and 48000 Hz for MPEG-1 and 16000, 22050 and 24000
Hz for MPEG-2.Microsoft has adopted the MPEG-2.5 "standard"
for use in their NetShow product and also in WAVE files using the NetShow
codec. MPEG data can be in stereo or mono and decompresses to 16-bit resolution.
MPEG compression is a lossy algorithm based on perceptual encodings, which
can achieve high rates of compression without a noticeable decrease in
quality. Typical compression rates are around 10-to-1.

mov

(pronounced
movie)

(.qt,
.moov, .movie)

MOVie

QuickTime
Movies: (.mov) This is the Apple/Macintosh standard for time-based multimedia
files. Versions 1.x support moving pictures, sound and later versions support
text. QuickTime 2.0 added MIDI tracks via a software synthesizer or external
synthesizer in 2.5 and later. QuickTime 2.0 or later and the QuickTime Musical
Instruments extension must be installed in order to play QuickTime MIDI
files. SoundApp should be able to play and convert from most all audio compression
formats, although QuickTime 3.0 doesn't support conversion from MPEG so
SoundApp can't either.
Files are compatible with IBM-based computers with a plug-in found in most
current Internet browsers using QuickTime for Windows.

swa

(pronounced
movie)

Shock
Wave Audio

Macromedia's
Shockwave streaming audio file

Other sound files
come in .AIFF (for Mac); .AU for Mac and UNIX; .WAV for the PC; and .RA for
Real Audio, a proprietary system for delivering and playing streaming audio
on the Web.

Information compiled
from Webopedia On-Line, UDI Latarre at www.why-not.com, Make Your Scanner a Great
Design & Production Tool by Michael Sullivan, and AskJeeves.com. On-line
Help in Adobe Photoshop and from my own teaching experience.